ex 3.
A∩N={2,0}
A∩Z={2,-3,0}
A∩Z+={2,0}
A∩Q={2. -3, -1/2, 0,(5), -6/3, 0, 1/0.(3), -3INTREGI SI 5/6}
A∩Q- ={ -3, -1/2, -6/3, -3INTREGI SI 5/6}
Exercitiul 5.
daca -x=-11/19=>x=11/19 si -(-x)=11/19
daca x=3,27=>- x= - 3,27 si -(-x)=3,27
daca -(-x)=31/7=> x=31/7 si -x=-31/7
daca -x= +0,7=>x= - 0,7 si -(-x)= - 0,7
daca x=-4/3=>-x=4/3 si -(-x)= - 4/3
daca -(-x)=-1/11=>x=1/11 si -x= - 1/11
